Metalloligand-anion frameworks: Tunable polarized luminescence and crystal-to-crystal transformation

Abstract

Noncovalent organic frameworks (NCOFs) are porous materials constructed by diverse intermolecular interactions. It is challenging to obtain polymorphic NCOFs with adjustable pores and high-performance polarized luminescence. Here, two polymorphic organometallic NCOFs, 1-α and 1-β, are presented from an iridium complex 1 based on the intralayer F···H hydrogen bonding and interlayer cation-anion electrostatic interactions. These metalloligand-anion frameworks display linearly polarized blue phosphorescence with a polarization degree of up to 0.91 and optical waveguide properties. The 1-α microcrystals doped with a ruthenium acceptor manifest a reversible response to Et₂O vapor, showing modulated energy transfer and polarized luminescence. The 1-α and 1-β microcrystals are transformed into another polymorphic 1-γ crystal by incorporating chiral (R/S)-carvone guests, affording tunable circularly polarized luminescence with a dissymmetry factor of around 0.1. This work provides a unique concept to obtain polymorphic NCOFs, demonstrating prominent potential in multifunctional optical and chiroptical applications.